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By C. Roos

"Nearly every input to a mine plan is based on an estimate. The estimates may be from sample data, historical information, models, or personal opinion, but in all cases, these values are simply expected values (means). In real life, we do not get to iterate the exact conditions at our mining operation many times to ensure that that average value is attained. The expected value also tells us nothing about the spread of values that that input might take on. The result is a significant amount of unquantified uncertainty in our mine plans. Unfortunately, it is often too expensive or time consuming to update planning processes and software. This paper presents a proof of concept spreadsheet scheduling tool that can be utilized to incorporate many geologic realizations (simulated models) into the mine scheduling process. While this POC is not intended to be a detailed model of uncertainty, it is to show that there are stepping stones available for mine planners to begin to embrace uncertainty and produce more achievable plans without requiring a significant change in their planning process. INTRODUCTION Mining companies have included quantifying uncertainty, or at least risk, as a requirement of project justification for many years, however many times this process lags behind the traditional mine planning process and the results are rarely used to improve the plan. Nearly every parameter used in a mine plan is an estimate and the mine planning engineer should recognize and even embrace the inherent uncertainty in those parameters and its effect on their forecast results. While many of the uncertainties are beyond the scope of the traditional mine plan (e.g. global market uncertainty, socio-political uncertainty, environmental uncertainty), some uncertainties can, and should, be included in the mine planning process. Many mining engineers have incorporated techniques such as Monte Carlo Simulation or Discrete Element Simulation to understand the range of productivity that can be expected for an operation but most still rely upon one estimated model for what is likely the critical component of technical uncertainty, the geologic resource. Modern geostatistical methods can provide multiple ore body realizations to provide a thorough unbiased “picture” of the geologic uncertainty but most traditional mine planning techniques are not formulated to allow for multiple (100-200) realizations of each material quality/grade parameter. Commercial software companies and research groups are progressing with development of tools that can incorporate geologic uncertainty, and even optimize extraction plans in the uncertain environment. Unfortunately, this author believes that a significant number of mining operations will not be able to adopt these techniques due to the computational requirements of the advanced techniques and the costs associated with implementing proprietary software. In an attempt to encourage mining engineers to embrace the inherent uncertainty in their mine plans, this paper presents a cost-effective alternative that can be developed in-house, at any mine, to schedule mid to long-term mine plans while continuously monitoring the uncertainty in the results. The author hopes that by demonstrating the usefulness of such a system that mining companies will encourage engineers, geologists, and geostatisticians to find ways to incorporate this powerful data into their processes and procedures."

Jan 1, 2017

By J. P. Wilson

The Tessenderlo-Kerley Leach process has been shown to be effective in the removal of residual copper from molybdenite concentrates. Concentrates of varying mineralogy, including those containing relatively large amounts of chalcopyrite, have been successfully leached on laboratory and pilot plant scales. The lixiviant system is ammonia and ammonium bisulfite with air / oxygen addition. An abrasive is added which greatly enhances the kinetics, and it is subsequently screened out and reused. The dissolved copper is easily recovered using existing technology. Extraction profiles, reagent consumptions, and mineralogical data are presented.

Jan 1, 1999

By P. R. Altringer, R. H. Lien, B. E. Dinsdale

The Bureau of Mines, U.S. Department of the Interior, is investigating biodegradation of cyanide as a means of decommissioning heap leach operations. Biological oxidation decreased weak acid dissociable (WAD) cyanide in process solutions from 50 to 170 ppm down to 0.1 ppm. The tests were conducted both in trickling column reactors, using quartz as the growth surface, and in upflow columns, using activated carbon as the growth surface. In addition, exploratory tests indicated that bacteria will destroy residual cyanide in leached ore. A flowsheet has been proposed for closure of heap leach operations in which the metals processing portion of the plant, possibly the carbon adsorption columns, or a collection pond is used as a bioreactor. The cyanide in the process solution is destroyed in the bioreactor and the treated water is used to rinse residual cyanide from the spent heaps. The water is recycled until the effluent WAD cyanide concentratio� meets discharge standards.

Jan 1, 1992

By T. D. Rourke, E. J. Cording, O&apos

INTRODUCTION Detailed investigation of a 60-ft-deep excavation in a mixed profile of sands and stiff clay was performed by the University of Illinois for the Washington Metropolitan Area Transit Authority (METRO). The work was coordinated through DeLeuw, Cather and Co., the General Engineering Consultant of METRO. Instrumentation was concentrated in a portion of braced excavation for the Gallery Place Station near the intersection of 7th and G Street. The early construction date, the 60 ft depth of cut, and the proximity of large buildings formed the basis for selection of this site as the focal point of observation and measurement. A history of lateral and vertical displacement is provided wherein movements which occurred during excavation to the full depth of cut and, subsequently, during station construction and the removal of braces are described in detail. Observations of preloading and the consequent brace loads and wall displacements are described. The effect of temperature change on brace loads is discussed and the measured apparent earth pressure for the 60-ft cut is provided. The paper discusses the relationship of lateral displacements of the cut wall to the construction procedure, and compares the lateral wall displacement with both lateral and vertical movement in the surrounding soil mass. Based on observed movement, the method by which displacement was predicted for a nearby 82-ft-deep excavation is described. The performance of the 82-ft-deep excavation has been summarized elsewhere (2).

Jan 1, 1974

By Y. J. Wang

Optimal sizing of a ventilation shaft is a classical subject in mine ventilation economics.. The shaft size is optimized by minimizing the sum of shaft-construction and ventilation-power costs, or owning and operating costs. The length and air quantity of the shaft are held constant, and the location of the shaft, affecting its depth, and construction and ventilation power costs, is not considered (Hartman, 1961; Lambrechts, 1974; Wang et al., 1978). This paper proposes an approach by which the location and size for a new pair of shafts (intake and return shafts) are optimized for a coal-mine ventilation network. Specifically, the problem is to determine the location and size for a new pair of shafts, and the distribution of air between the new and old shafts so that the combined cost of shaft construction and ventilation power is minimized. The shaft length or depth corresponds to the height of overburden at any shaft location. To simplify the problem, the shaft locations will be limited to the line along the main or submain entries, and the connection entries at the shaft bottom neglected. In order to calculate the ventilation-power cost, the air power of the system should be determined. This in turn requires the calculations of the air quantity and pressure of each fan in the network, satisfying Kirchhoff's laws and Atkinson equation. After obtaining the air power, the cost calculation is straightforward. In the following, we shall assume that the resistances of all airways, and the quantity for each mining section, which is controlled by adjusting the air regulator, are all known. The resistances for the shafts are determined from the estimated friction factors, and shaft dimensions and lengths. Furthermore, it will be assumed that the fans can be selected to meet the duties called for by any network solutions.

Jan 1, 1982

By R. Y. Wan, J. R. Parga, J. D. Miller

The direct recovery of precious metals from a1kaline cyanide solution is frequently accomplished by the well-established Merrill-Crowe process involving zinc-dust cementation. This is particularly true for silver. Plant data from two operations are presented and analyzed in terms of intrinsic reaction features. In such Merrill-Crowe plants a plate-and-frame filter press acts as a semicontinuous fixed-bed reactor with a distribution of particle retention times. For the plants studied, 99Yo of the silver is recovered with a solution retention time of less than 2 min. Differences in plant operating conditions and product characteristics can be related to the nature of the surface deposit of silver which forms on the zinc particles. From laboratory experiments and plant samples it has been found that the presence of lead in the system activates a change in the silver deposit morphology to the dendritic state which affects the rate of silver deposition as well as the filter cake porosity. Finally the plate-and-frame press is considered from an engineering perspective as a semi- continuous fixed - bed reactor to describe the behavior of the system.

Jan 1, 1987

By S. D. Thompson, L. Adler

This study reviews and analyzes the empirical methods available for designing the capacities of coal mine gathering belts. The analyses lead to recommendations concerning the application and implementation of each empirical method. Operations research techniques, mainly simulation models, are also briefly mentioned, and a few recommendations are made concerning their selection and application. The objective of the study is to provide a reliable basis for the practicing engineer to properly select, apply, and implement a capacity design method.

Jan 1, 1988

By J. Peck, M. J. Scoble, C. Hendricks

This paper is based on field studies in North American surface mines. The work involved the adaptation of microprocessor-based instrumentation to monitor various operating parameters on-board rotary blasthole drills and mining shovels. Following a review of instrumentation and monitoring methodology - drawing on experience gained under field conditions-the paper will focus on the application of monitoring technology within the framework of an Integrated Equipment Monitoring System. Such a system will permit real-time performance evaluation of key equipment involved in surface mine production. Drill performance monitoring has been demonstrated through work to date, to provide significant input into blast design, reserve estimation, mine planning and production control processes, through an improved facility for ground characterization. Monitoring excavation equipment has been proven valuable in assessing how effectively the input from drill monitored data has been used in the evolution of blast designs. This specifically refers to assessing blast efficiency through measuring associated levels of excavator performance in relation to muckpile characteristics. The medium-term goal of equipment instrumentation and monitoring has been to assist mines in optimizing the overall rock breakage and handling process. Based on the reported results, this has been accomplished. Long-term efforts now concern using a greater understanding of equipment performance and response to varying operating conditions as a foundation for the implementation of mining automation.

Jan 1, 1993

By James M. Prudden, Jon C. Sprague

Valdez Creek Mining Co. properties consist of multiple intersecting paleo-placer channels containing appreciable quantities of coarse gold. Reverse circulation drilling, combined with geophysics, is used for both exploration and development reserve determination. Classical drill-blast-load-haul open pit mining techniques used for the 22,000 cubic yard per day production schedule required modification to compensate for arctic winter operating conditions. High wall stability problems within the glacial sediment overburden necessitated developing multiple dewatering methods and variable pit slope designs to eliminate unstable pit wall conditions. Processing mine run fluvial gravels utilized a classical winter protected screening plant-sluice box recovery system enjoying high metallurgical recoveries and zero discharge tailings disposal.

Jan 1, 1987

By Dan Xu, Song. Gaofeng, Zhen Wei, Zhihe Wang

"With decades of development and exploitation of coal resources, the first batch of coal-based cities in China are faced with the challenge of economic shrinkage and environment deterioration due to the rapid resource exhaustion and single industrial structure. Nowadays, as a policy instrument for sustainable development, a nationwide circular economy mode has been implemented during the design and planning of new coal mines to address the challenges arising from economic depression, energy shortage and environmental pollution. It should be mentioned that several national coal bases and most of constructing and planning coal mines are located in the underdeveloped areas in the Midwest of China which means that the distance between supply source for energy resources and the demand market is significantly increased. Moreover, the eco-environment vulnerability in these rural areas should be taken into serious consideration. Therefore, after comparison and analysis with several successful coals based and diversified circular industry chains, this paper presents a case study on the circular economy park (CEP) in the northwest of Shanxi Province. Through discussion and evaluation of ‘1+3’ mode in the CEP, this paper aims to enhance the understanding of coal mine sustainable development and shed light on the relationship between resources exploitation and local economic development.1. Introduction Earth's fossil energy resources are crucial to both economic prosperity and human well-being. Taking coal mining and consumption as an example, coal has been widely used to generate electricity since the 1880s, and more than 40% of the electricity globally is provided by coal nowadays. However, as one of the largest worldwide anthropogenic sources of carbon dioxide releases (39% of global CO2 emissions), the extensive excavation and utilization of coal have brought a series of side effects to both natural environment and human health (Wikipedia 2017). As the largest coal producer and consumer in the world, China is leading the list over the past decade (as shown in Figure 1) (BP 2016). The excavation and utilization of coal resources have made a crucial impact and irreplaceable contributions to China’s industrial development and economic prosperity (Long and Zhang 2009). However, most of the air pollution in China are also attributed to the simplified and extensive exploitation of coal resources, e.g., 90% of SO2, 67% of NO, 70% of smoke ashes, and 70% of CO2 in 2016. In recent years, most of North China and the developed coastal areas were wreathed by smog due largely to the oversimplified extensive utilization of coal, suggesting that the development patterns of coal utilization need to be reshaped so that both the biosphere and humanity could thrive equally."

Jan 1, 2017

By Claude Hébert

The Grenville structural province, a 400 km-wide belt of Precambrian metamorphic rocks which crosses the province of Québec in a northeasterly direction, is the host of several wollastonite occurrences. Most of these are found in marble and calc-silicate rocks enclosed within or located near intrusive bodies. Reconnaissance and detailed mapping of such zones have helped to identify areas of interest for wollastonite exploration. The most important zone is located in the huge Lake Saint-Jean anorthosite massif in the central part of the Grenville. A recent geological mapping project has revealed the presence of wollastonite in metasedimentary faulted remnant of the roof. The main occurrence consists of diopside and wollastonite in a zone at least 3 km long and 150 m wide. Preliminary sampling suggests and average grade of 50 percent wollastonite with an aspect ratio of 151. Other wollastonite deposits occur in the western part of the Grenville, mainly north and west of Montreal, where the Morin anorthositic complex and a large syenite mass intrude the metasedimentary rocks of the Grenville Supergroup. Marble bands with up to 70 percent wollastonite occur locally at the southern margin of the complex or as an inclusion in the syenite. Significant wollastonite occurrences have recently been found in the eastern part of the Grenville. One of them is located in metamorphosed calcareous rocks which are part of the granulite facies Manicouagan metamorphic complex. A representative sample analyzed 54 percent wollastonite. Farther south, an inclusion diopside-wollastonite gneiss containing an estimated 40 percent wollastonite occurs at the margin of the Pentecôte River anorthositic complex.

Jan 1, 1995

By C. Gregory Knight

Adequate planning for the development, operation, and reclamation of a surface mine requires attention to present and future uses of land, both on the mine site and in the mine vicinity. This paper outlines land use implications of surface mining, and suggests procedures that could link mine planning, mine operation, and reclamation to more general land use concerns. Mining is viewed as a temporary use of land that may irretrievably commit land resources away from some future activities, but may allow other uses, some of which may have been impossible without mining. The paper accepts the premise that surface mining should attempt to minimize environ-mental damage and to maximize future alternative uses of land by appropriate reclamation. I. The Effect of Surface 1'1ining on Land Use Surface mining is a temporary utilization of the land most often criticized because the disturbances it creates are of far greater duration than the actual extractive operation, Resource recovery disrupts existing activity on the land, at least temporarily, and

Jan 1, 1977

By M.P. ROY, ASHISH K. VISHWAKARMA, A.K. MISHRA, P.K. SINGH, VIVEK K. HIMANSHU

Principal component analysis (PCA) is one of the dimension reduction techniques widely used to classify data based on features. Ground vibration is a major hazard arising from rock blasting operations, and accurate prediction of the vibration is necessary for designing controlled blasting parameters. Most of the widely accepted predictors of ground vibration consider the maximum explosive charge weight per delay (MCPD) and distance as the parameters responsible for ground vibration, but mining sites with bigger production targets have varying geometrical parameters to suit the excavator utility. Accordingly, other blast design parameters will also have impacts on ground-vibration intensity. A blast vibration predictor considering all the blast design parameters would be complicated, and some of the parameters will have overlapping contributions to ground-vibration intensity. Data classification using PCA is a feasible solution, and regression analysis may be performed to develop predictors using the classified input data. In this study, PCA was used along with multivariate logarithmic regression to predict ground vibration, and the performance of this technique to predict ground vibration was compared with the performances of various existing empirical predictors. The evaluation suggests that the predictor with logarithmic regression followed by PCA performs better than the existing empirical predictors.

Nov 1, 2022

By David Newman

"Horizontal stress can have a profound effect on the stability of an underground limestone mine. The presence of horizontal stress is usually determined once the mine has been developed and the orientation of headers and crosscuts are well established. Multiple attempts are typically made to control roof falls without re-orienting the mine. Once the decision has been made to change the orientation, pillar centers, mine opening widths, and the question of how to determine the correct orientation must be answered.A case history is presented to illustrate how geologic structure, ground conditions and roof falls in adjacent mines, the World Stress Map (Heidbach et al., 2016), in-mine measurement of “cutter” roof orientation, the orientation of strata offset (cats eyes) within borescope holes, and the diametral deviation method of determining horizontal strain from drill core were used to establish the most likely range of horizontal stress.The main headers were re-orientated in a direction parallel to the median of the range of horizontal stress. The crosscuts were angled 60° to the headers to avoid being perpendicular to the horizontal stress direction. Pillar centers and opening widths were increased in the favorable stress direction of the mains and decreased in the less favorable crosscut orientation. The major principal horizontal stress magnitude was estimated using the strain measurements from the diametral deviation method and elastic modulus obtained through testing.INTRODUCTIONOver the past decade, there has been a significant increase in the number of underground stone mining operations in the United States. As stripping ratios at surface quarries become uneconomical and reach the extent of the mineral boundary, coupled with the encroachment of urban development on previously rural mining operations, the remaining mine reserves are best accessed through underground development.Although the majority of underground limestone mines in the Midwest are in relatively flat lying deposits with minimal geologic structure, many Appalachian mines are in folded and faulted environments. Tectonic horizontal stresses associated with multiple orogenic episodes are locked in the formation and are released as the underground mine is developed.A common misconception is that horizontal stress impacts are more prevalent at shallow depths where the ratio of horizontal to vertical stress may be high. However, field observations and academic research indicates that horizontal stress conditions may be encountered at any depth due to the tectonic compression of the limestone formation (Esterhuizen et al., 2007; Dolinar and Esterhuizen, 2007; Iannacchione et al., 2003; Slaker, Murphy, and Miller, 2017; Kuhnhein and Ramer, 2004). This paper outlines mine design and layout guidelines for the mitigation of horizontal stress impacts on underground stone mining operations through a case history example. This approach to mine planning and the ability to anticipate horizontal stress can significantly improve future production of multiple levels (Newman and Newman, 2019). As underground stone production continues at deeper depths and in more geologically and geometrically complex mining conditions, an emphasis on ground control and the anticipation of horizontal stress can provide safer and more productive single and multiple level mining operations."

Jan 1, 2019

By V. O. Tenorio, D. Tolmachoff, K. Willa Brown, K. J. Kingsbury, J. B. Nickels, G. J. Nail

A major design feature to consider from the initial pioneering works until reaching full mine production of icy regolith at the South Pole of Moon will be the ramp. This will allow the access of equipment and personnel in and out of the excavation area. Although most of the requirements considered when designing a ramp on the Earth are similar, the fact of working in low gravity, with zero atmosphere, the potential exposure to high radiation, extreme temperature levels and drastic changes of illumination, from intense light to total darkness, are new factors to be included. Transversal sections are obtained according to the progression sequence of the production levels, with changes in length, gradient, friction factor of the terrain and curvature when required by the location characteristics and the specification of the equipment utilized. A MATLAB script was developed to calculate all the variables, in order to obtain 3D generated surfaces from the range of possible profiles.

Mar 2, 2022

By Marcos de Paiva Bueno, Leonardo Ribeiro Lara, Rajiv Chandramohan, Thiago de Almeida, Greg Lane

This paper explores the impact of the significant difference between the number of geochemical assays conducted for grade estimation and the number of comminution tests performed for throughput and performance forecasting. Both grade and throughput are key factors in determining the project. We analysed 154 feasibility study reports to assess the impact of sample frequency for comminution test work on project revenue. This disparity in size between assay and comminution data arises because geological and resource-grade risks cannot be managed without extensive geochemical testing, whereas comminution risks are traditionally mitigated through design methods and the use of contingencies. This approach is partly due to the relatively high cost and large sample requirements associated with traditional comminution tests. Our analysis demonstrates that insufficient comminution sampling and testing leads to uncertainties in throughput forecasts, creating significant financial risks. Data from the feasibility studies show that a 1% change in mill throughput can result in up to a 5% variation in Net Present Value (NPV), underscoring the sensitivity of project economics to operational performance. Building on previous work, we reference studies that reveal how low frequency of comminution testing can increase uncertainty in mill throughput forecasts and increase financial risks. We propose an approach that optimises the number of comminution samples tested to enhance forecast accuracy and reduce NPV variance. By adopting this approach, mining projects can improve financial reliability and mitigate risks associated with underperformance in SAG and AG mill-based operations.

Feb 1, 2025

By F. Segobia, M. Portal, F. Ysla, A. Mujica, L. Goicochea

The “Building Our Future” project is a collaborative initiative between the UNC SME Student Chapter and the Water and Earth Museum (MAT) of Asociación Los Andes Cajamarca (ALAC), both corporate entities of Newmont Yanacocha. Its mission is to promote responsible and sustainable mining among new generations while fostering a culture of equality and respect. This comprehensive educational program integrates sustainable development goals and includes workshops led professionals and external experts who share their personal stories to inspire students from rural and urban educational institutions to follow their dreams. Additionally, for this year 2024, the project development and implemented an interactive mobile application that educates users about the use of minerals in everyday life through four levels: Minerals in the Home, Minerals in Medicine, Minerals in Transportation, and Minerals in Agriculture. This multi-faceted approach seeks to raise awareness about the importance of mining in Peru’s economic, environmental, and social development, ultimately fostering a new generation of informed and engaged citizens who understand the vital role of mining in a sustainable future.

Feb 1, 2025

By Michael Honerkamp, Clemens Mann

A quarry is not a static, but a dynamic structure that greatly affects the appearance of the surrounding area. Excellent planning is required today to cope with this continual change. In this paper several case studies are presented where computerized three-dimensional visualization has been successfully applied.

Jan 1, 1996

By J. -C. Roegiers, M. Thiercelin

Accurate toughness determinations are difficult to achieve in the case of soft or heterogeneous rocks. The existence of a large process zone ahead of the crack tip makes the determination of the apparent toughness crack length dependent, in the case of subsized specimens. In order to use practical size specimens, the authors propose a new toughness test, the Modified Ring Test, which pre- vents a largely developed process zone to form ahead of the crack tip. This test has also the advantage that its geometry is core-based. Numerical and experimental results are discussed.

Jan 1, 1986

By J. L. Post, L. Borer

Small seams of fibrous tremolite and actinolite commonly occur in many California counties. A number of larger seams of this fibrous material were mined from 1882 until about 1955. The fibers from these mines were used for making acid filters, battery cases and fire-resistant paint. With increasing population, new residential areas are being developed in the foothill regions, leading to increased contact with seams of fibrous amphiboles. These forms of asbestos can be particularly dangerous to human health. Thus, it is necessary to determine the locations of these mines and adjacent veins and to identify the specific amphibole minerals present.

Jan 1, 2003